The invention relates to a heat engine for a motor vehicle.
The invention relates more specifically to a heat engine, particularly for a motor vehicle, of the type which comprises at least one engine block rotatably receiving a crankshaft and a housing fixed to the engine block, which rotatably receives a pair of parallel balance shafts, namely a primary shaft and a secondary shaft, which are provided with eccentric weights and which are rotated by the crankshaft, of the type in which a ring gear rotationally connected to the crankshaft permanently meshes with a first pinion carried by one end of the primary balance shaft, and of the type in which a second pinion carried by the end of the primary balance shaft meshes with a pinion carried by one end of the secondary balance shaft.
There are numerous known examples of heat engines in which the balance shafts are carried by a housing which is attached to the engine block.
EP-A1-1 445 509 describes and illustrates an engine in which the housing comprises an intermediate shaft for driving the balance shafts, this intermediate shaft itself being driven by a camshaft of the engine by means of a toothed belt.
For the correct angular positioning of the intermediate shaft with respect to the camshaft, the end of the intermediate shaft comprises two non-symmetrical flats forming location elements for positioning the intermediate shaft with the aid of a suitable spanner before it is mounted.
This solution is not satisfactory, since it creates numerous difficulties for the operator responsible for the mounting.